Liquid blending systems, such as those used to mix beverage syrup and water, typically introduce a stream of beverage syrup and a stream of liquid such as water to a mixing chamber. In the mixing chamber, the syrup and the liquid mix with one another to provide a partially blended beverage. The partially blended beverage typically then flows to a static diffuser, which functions to fully blend the beverage. One type of diffuser includes a series of plates in a stacked arrangement. The partially blended beverage is radially expanded by the surface of the plates, and the spaced arrangement of the plates causes a cascading effect of the beverage through the diffuser. The beverage is subjected to an expanding and shearing process as it passes through diffuser, which ultimately results in a fully blended beverage.
One of the drawbacks of conventional beverage blending systems is the lack of blending that occurs within the mixing chamber upstream of the diffuser. That is, most of the mixing of the beverage syrup and the liquid occurs at the static diffuser rather than from the introduction of beverage syrup to the flow of liquid, or vice-versa. While there may be some dispersion of the beverage syrup into the stream of liquid, or vice-versa, for the most part, these separate components remain relatively separate from one another until presented to the diffuser, which can result in a syrup slug being presented to the diffuser. While the diffuser will expand the slug and provide a certain amount of blending, it is possible for the slug to overwhelm the diffuser and result in a poorly blended beverage.
Poor mixing of syrup and liquid can result in an incorrect ratio of syrup to liquid medium. In the past, any such imbalances have been accounted for by passing the syrup and liquid through an averaging tank. While this functions satisfactorily to even out liquid/syrup ratios, it involves an added piece of equipment that requires installation and maintenance, as well as an additional step in the process.
In addition, conventional blending systems have utilized pump control to regulate the flow of syrup and liquid along respective supply conduits to the mixing chamber. Nipple valves are usually provided at the dispensing ends of each supply conduit. When the pumps are shut off at the end of a dispensing cycle, forced flow of syrup and liquid along the supply: conduits ceases. However, because of the density of the syrup, it is not uncommon for some syrup to leak out of the nipple valve into the mixing chamber. If the liquid medium is also leaked into the mixing chamber, the leakage of syrup would be less problematic. However, the less dense liquid medium typically does not leak past the nipple valve at the end of the liquid supply conduit. The introduction of residual of syrup to the mixing chamber can disturb the ratio of syrup and liquid in the mixing chamber when the dispenser is cycled back on.
The above-described lack of precision in controlling the amounts of syrup and liquid medium can be exaggerated when additional ingredients are added, such as flavoring or the like.
The present invention seeks to overcome the drawbacks of conventional blending systems by providing a blending system that uses countercurrent injection to improve the blending of a concentrate, such as beverage syrup, with a fluid medium, such as water. Introducing concentrate and fluid in opposed flows into a mixing area improves the dispersion or blending of concentrate in the liquid medium, which provides more efficient and better blending downstream, such as by a static diffuser.
Additionally, in one embodiment, respective check valves are used to control the flow of concentrate and liquid medium from respective supply conduits into the mixing chamber. The check valves provide improved performance against backflow and leakage.
The present invention also reduces the occurrence of syrup (or concentrate) slugs, provides consistent pre-diffuser distribution of concentrate, and eliminates the need for large averaging tanks typically required in beverage blending systems.
Therefore, in accordance with one aspect of the invention, a fluid mixing apparatus for mixing a first fluid and a second fluid is provided. The mixing apparatus includes a mixing chamber having an inlet and an outlet, with the inlet designed to pass a stream of the first fluid along a first flow direction. A countercurrent injection nozzle is disposed within the mixing chamber and is operative to inject the second fluid into the stream of the first fluid along a second flow direction that opposes the first flow direction. As the second fluid exits the countercurrent injection nozzle, the second fluid collides with the first fluid and causes turbulent flow of the two fluid components within the mixing chamber. This collision and turbulent flow causes immediate dispersion of the second fluid and, ultimately, distribution of particles of the second fluid within the first fluid.
In accordance with another aspect of the invention, a multi-stage blending system is provided, and includes a mixing chamber having a fluid inlet and a fluid outlet. The fluid inlet is configured to receive a primary fluid stream. The system further includes a plurality of spaced valve bodies arranged between the fluid inlet and the fluid outlet. A respective mixing volume is defined between successive valve bodies. Each mixing volume has a respective countercurrent injection nozzle that is configured to inject a secondary fluid into the primary fluid stream. Thus, within each mixing volume, the collision of the secondary fluid into the primary fluid stream is used to distribute the secondary fluid throughout the primary fluid stream.
The present invention may also be embodied in a method. Accordingly, another aspect of the invention includes a method of mixing a first fluid and a second fluid. The method includes introducing a first fluid into a mixing chamber having an outlet and introducing a second fluid into the mixing chamber along a flow path that opposes the flow path along which the first fluid flows within the mixing chamber toward the outlet.
It is therefore an object of the invention to provide a blending system providing improved blending.
It is another object of the invention to provide a blending system that does not include an averaging tank.
It is another object of the invention to provide a beverage blending system with reduced leakage of concentrate into a mixing chamber.
Other objects, features, aspects, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.